The influence of culture pH on the metabolism of Gluconobacter oxydans was determined. An acidic milieu during growth of the organism enhances the oxidation rate. The CO2 evolution rate representing the assimilation of the product is inhibited by a low pH value. Growth of the bacteria is possible both on glycerol and DHA in separate phases, which Is not a controlled as diauxic growth. Product formation follows Luedeking-Piret kinetics.